CompilerWarnings: Update minimum supported clang version for JUCE_BEGIN_NO_SANITIZE

Clang versions 5 to 8 inclusive seem to struggle to compile JUCE when
JUCE_BEGIN_NO_SANITIZE is used. This is unexpected, as simpler programs
using the same macro definitions compile correctly on clang 5.

modules/juce_core/system/juce_CompilerWarnings.h

@@ -202,7 +202,7 @@
 #if JUCE_MAC || JUCE_IOS
     #define JUCE_SANITIZER_ATTRIBUTE_MINIMUM_CLANG_VERSION 10
 #else
-    #define JUCE_SANITIZER_ATTRIBUTE_MINIMUM_CLANG_VERSION 5
+    #define JUCE_SANITIZER_ATTRIBUTE_MINIMUM_CLANG_VERSION 9
 #endif
 
 /** Disable sanitizers for a range of functions.